In general, particles of mineral matter are used as an inorganic filler in a variety of applications, and especially in paint formulations. The paint formulations likewise comprise a number of other constituents, each having a defined function within the formulation, and especially thickeners, whose function is to control the rheology of the formulations, both at the stage of their manufacture and during their transport, their storage, or in the course of their implementation. The diversity of the practical constraints within each of these steps makes for a multiplicity of different rheological behaviors.
A wide variety of thickeners exist for paint.
Among those thickeners, one can mention natural thickeners based on cellulose of type HEC (hydroxyethylcellulose). One can also mention thickeners called “associative” thickeners, and especially associated thickeners of acrylic variety, described especially in documents EP 0 577 526 A1, EP 1 778 797 A1, EP 2 108 007 A1, EP 2 114 378 A1, EP 2 303 982 A1, FR 2 950 061 A1 and FR 2 956 862 A1.
HASE thickeners are traditionally added at the end of formulation of the paints (post addition) or alternatively in two steps (at the start of formulation, at the pasting stage, and post addition). The reason is that the paint formulator is aiming conventionally to obtain a sufficiently high viscosity during pasting, and in order to achieve this may add some or all of the thickener during pasting. With the aim of simplifying the manufacturing method, the formulator is ready to consider any solution resulting in high viscosities without any need to add additives.
Nowadays there is a demand on the part of formulators to simplify the work of formulating paints. Similarly, for reasons of cost, there are demands for a reduction in the amount of additives in the formulations.
This is the context for the present invention.
More specifically, an object of the present invention is the use of a thickening polymeric aqueous emulsion for surface treating particles of mineral matter.
The work of the paint formulator is thereby simplified through the omission of a compound to be introduced.
The inventors observed, moreover, that by using said surface treated particles of mineral matter, it was possible to reduce the total amount of thickeners required, relative to the independent introduction of particles of mineral matter and then of thickener, while retaining the same rheological profile.
Moreover, the inventors observed that the gloss values of paints containing treated particles of mineral matter of this kind were very greatly improved relative to the paints in which the particles of mineral matter were introduced independently of the thickener.
The polymeric aqueous emulsion used in the context of the present invention has been the object of two patent applications filed in the name of Coatex, under numbers WO 2013/064761 and WO 2013/064763.